Why can't I print this Soup Pot with lid on my Makerbot z18

[3dspider]

hmmm.. did you fix this oddity ?
http://i.imgur.com/RdFHEwO.png <top
http://i.imgur.com/b2ziH9o.png <bottom
http://i.imgur.com/FUG1nAV.png <side (cut away)